Safecast Air Prototypes

Friday January 29th, 2016

If you’ve been following along at home you know that at Safecast we’ve been thinking about measuring air quality for quite some time. More than once we’ve jumped in only to be disappointed with the results, pushing us back to square one. One of the key tenets at Safecast is that we must be able to stand behind the data we publish 100%, so to that end we need to trust the sensors we’re putting out into the world. The fact is we just haven’t had that kind of confidence in relation to the air quality tests we’ve conducted, until now. Towards the end of 2015 we built and deployed the first Safecast air sensor that we think is actually a viable prototype. We call this Prototype 001. This device is designed to be a static sensor, permanently installed in a single location with fixed power and internet for the data consumption. It’s also huge. You can see in the photo below, the tiny little PCB with the display – that’s the same footprint as the bGeigie Nano, so you can get a good idea of the overall size. It’s not exactly something you can just throw in your backpack.

As mentioned in previous posts, one of the hurdles with measuring air quality has been deciding what “air quality” actually means, as it isn’t really a technical term, and in different places different things are more important to measure. For our devices we decided to take a modular route so that different sensors could be plugged in to any Safecast Air device to customize what is being measured in that area. To complicate matters, there isn’t yet a reliable way to collect particulate data in a mobile device, so for any sensor we want to use collect particulate data, for now that means it’s going to be a static device. With Prototype 001 we’ve included particulate (in PM10, PM2.5 and PM1.0) as well as a bank of 6 gas sensors (here measuring 3 gases, 2 sensors for each). It’s big and filled with some extra debugging hardware, but like our first generation radiation detection hardware, which was also bulky and inelegant, it works. Prototype 001 was built in Los Angeles and is currently deployed in Japan for testing.

While Prototype 002 is also designed to be a static sensor, we wanted to make it a little easier to transport to wherever it was going to be installed. We reduced the size by almost 75% but kept the same sensor set up.

Because this model can easily fit in a suitcase, we’ve been able to carry it around and collect samples in various locations. Over the past 2 months this prototype has been set up and collected readings for several days at a time in 6 different cities around the world. It’s currently running in Los Angeles.

Prototype 003 is more purpose-specific and was designed to be very mobile and focused on measuring only methane. Readers might be aware of the Porter Ranch Gas Leak outside Los Angeles; we knew people directly affected by this and wanted to quickly get a device in their hands that might provide some useful info. We’re still very much in the beta testing stages of this, but prototype 003 is battery powered and currently deployed at the home of someone evacuated from Aliso Canyon, so we’re hopeful that the data it collects will be useful.

Air Prototype 003 (Mobile, single gas. Half the size of prototype 002)

Over the coming weeks we’ll build and deploy several more prototypes in various configurations to start seeing what works best and would would be useful to include in a kit, similar to the bGeigie Nano. We also hope to have visualizations soon of the data we’ve collected, and provide access to it via our API. As with all Safecast projects this is open source from top to bottom and you can help look over the code on GitHub if that is your thing, or join the discussion in our Air Quality mailing list (although admittedly most of the discussion and work is happening in our slack channel these days – let us know if you’d like to join in).